To stimulate interest in the sport, a competition was organised at the Wasserkuppe in August 1920 which became an annual event later known as the Rhön contests.

This aircraft, the FVA-1 Schwatze Düvel, was an internally braced, thick airfoil cantilever monoplane with large trousers over landing skids on each side.

To keep costs low the aircraft was largely covered in black muslin fabric, donated by the father of a student's girlfriend.

[1] The longest flight that day was 1.830 km (1.137 mi) with a duration of 142 s, much further and longer than the previous best in the competition, set by Pelzner in his hang glider, of 452 m (1,480 ft) in 52 s.[1] The FVA-1 flew again on 7 September in a brisk 30 kn (56 km/h; 35 mph) wind, actually gaining 30 m (98 ft) in height whilst hovering over the ridge, before landing.

Several were produced to order and at least one of these aircraft was fitted with a wheeled undercarriage replacing the main skids and one other was used by Wolfgang Klemperer to research glider launching from balloons.

On 30 August he flew the Blaue Maus to a world record distance of 4.6 km (2.9 mi) during a 13-minute flight to Gersfeld and back.